Dropbox is upping its game for business users. The cloud-based storage and sharing company has announced new security, search and other features that it hopes will boost its appeal beyond the 80,000 businesses that currently subscribe.

The company launched the beta of its Dropbox for Business last fall. Its 300 million users across its entire service account for more than a billion files being saved to Dropbox every day.

Dropbox is steadily increasing its international footprint. About 70 percent of its paying business users are outside the U.S. A quarter of all Dropbox customers are in the U.K., which is the company's second largest market. Its first Australian office opened in Sydney in April, and this week the company said it will be opening its first London office. Dropbox reports that its base in the U.K. has grown 100 percent over the last year.

Security, Shared Folders

A key focus of the new enhancements is security, a top concern for using cloud-based services. Link-sharing now offers password , plus there's now a link expiration so that access to the materials is not unlimited by time. Such sharing is often conducted with people outside a company, many of whom do not have Dropbox accounts, and shared files are often intended for short-term file access.

Shared folders can also now be set as Read-Only, so that administrators can determine who can view and edit, as opposed to those who can only view.

In addition to the fact that security is an ongoing cloud issue for IT departments, it's been a particular sore spot recently for Dropbox. Former National Security Agency (NSA) contractor Edward Snowden, now in Russia, has said that Dropbox was "hostile to privacy."

He called the company "a wannabe PRISM partner," because it was reportedly in line for that NSA surveillance program, and he praised competitors like Spideroak as providing greater security because its own employees cannot access encrypted user data.

Full Text Search

Additionally, Dropbox has come under heavy criticism for adding former U.S. Secretary of State Condoleezza Rice to its board of directors because of her ties to the administration of former resident George W. Bush, which had its own surveillance and trust controversies.

On the search front, Dropbox for Business is now a full text search for all kinds of documents, including presentations and spreadsheets. Previously, search was limited to file names. A new feature in its previously-announced Project Harmony enables a user to see who else is currently sharing a document. The Android app now offers a preview of Microsoft Office documents.

Developer tools have been expanded, and two new APIs allow previews and shared folders to be implemented in other companies' apps.

Laura DiDio, an analyst with Information Technology Intelligence Corp., told us that "the security component cannot be overstated" in terms of its importance to businesses. She also pointed to Dropbox's continued nurturing of outside developers, given that "apps are the lifeblood of any platform."